Multi-tier deterministic networking

ABSTRACT

Various example embodiments for supporting multi-tier deterministic networking are presented. Various example embodiments for supporting multi-tier deterministic networking may be configured to support provisioning of deterministic flows in multi-tier deterministic networking. Various example embodiments for supporting multi-tier deterministic networking may be configured to support adaptive deterministic routing in multi-tier deterministic networks. Various example embodiments for supporting multi-tier deterministic networking may be configured to support score-based deterministic routing in multi-tier deterministic networks. Various example embodiments for supporting multi-tier deterministic networking may be configured to support adaptive deterministic routing and/or score-based deterministic routing in multi-tier deterministic networks based on analysis of a state representation for path and/or sub-path selection in multi-tier deterministic networks. Various example embodiments for supporting multi-tier deterministic networking may be configured to support hierarchical resource allocation and deallocation in multi-tier deterministic networking, optimal route finding in multi-tier deterministic networking, and so forth.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.17/184,108, filed on Feb. 24, 2021, and entitled MULTI-TIERDETERMINISTIC NETWORKING, which is hereby incorporated by referenceherein in its entirety.

TECHNICAL FIELD

Various example embodiments relate generally to communication systemsand, more particularly but not exclusively, to deterministic networking.

BACKGROUND

In various communication networks, various communications technologiesmay be used to support various types of communications.

SUMMARY

In at least some example embodiments, an apparatus includes at least oneprocessor and at least one memory including a set of instructions,wherein the set of instructions is configured to, when executed by theat least one processor, cause the apparatus to receive, by an element ofa communication network configured to support a set of interfaces of aset of nodes of the communication network, a request to resolve arouting request for a deterministic flow, determine, by the elementbased on state information for the set of interfaces, a selectedsub-path for the deterministic flow, wherein the state informationincludes scheduled sub-path information for a set of scheduleddeterministic flow sub-paths allocated on the set of interfaces andcandidate sub-path information for a set of candidate deterministic flowsub-paths requested on the set of interfaces, and send, by the element,a response indicative of the selected sub-path for the deterministicflow. In at least some example embodiments, the scheduled sub-pathinformation includes, for each of the interfaces, an indication of a setof deterministic resources allocated over time on the respectiveinterface for the set of scheduled deterministic flow sub-paths. In atleast some example embodiments, the candidate sub-path informationincludes, for each of the interfaces, an indication of a set ofdeterministic resources requested over time on the respective interfacefor the set of candidate deterministic flow sub-paths. In at least someexample embodiments, the set of candidate deterministic flow sub-pathsincludes a subset of candidate deterministic flow sub-paths from a setof deterministic flow sub-path requests received by the element, and thestate information includes a sub-path backlog parameter configured torepresent a remaining portion of the candidate deterministic flowsub-paths from the set of deterministic flow sub-path requests receivedby the element. In at least some example embodiments, the stateinformation includes at least one of latency requirement information orjitter requirement information. In at least some example embodiments,the state information includes at least one of a flow backlog metric, alocal key performance indicator, or a global key performance indicator.In at least some example embodiments, to determine the selected sub-pathfor the deterministic flow, the set of instructions is configured to,when executed by the at least one processor, cause the apparatus todetermine, by the element based on a sub-path determination agentsupported by the element, a set of feasible sub-paths for thedeterministic flow and select, by the element from the set of feasiblesub-paths for the deterministic flow based on scoring of the set offeasible sub-paths for the deterministic flow by the sub-pathdetermination agent, the selected sub-path for the deterministic flow.In at least some example embodiments, the sub-path determination agentis configured to determine the set of feasible sub-paths based on aneural network. In at least some example embodiments, the neural networkincludes a set of internal elements trained based on historicalinformation, and the set of feasible sub-paths is determined based on aset of internal parameters quantifying weights between internalelements. In at least some example embodiments, the sub-pathdetermination agent is configured to determine the set of feasiblesub-paths based on a score calculator. In at least some exampleembodiments, the score calculator includes at least one of a functionconfigured to score sub-paths based on respective durations of thesub-paths or a function configured to score sub-paths based onrespective alignments between the sub-paths and resource availability.In at least some example embodiments, to select the selected sub-pathfor the deterministic flow, the set of instructions is configured to,when executed by the at least one processor, cause the apparatus toreceive a vector including, for each of the feasible sub-paths in theset of feasible sub-paths, a recommendation identifying the respectivefeasible sub-path and a score associated with the respective feasiblesub-path and select the selected sub-path based on the scores associatedwith the feasible sub-paths. In at least some example embodiments, theset of instructions is configured to, when executed by the at least oneprocessor, cause the apparatus to send, by the element toward thesub-path determination agent, a state update signal configured to updatethe state information maintained by the sub-path determination agent,initiate, by the element toward the sub-path determination agent, a picksignal configured to request that the sub-path determination agentdetermine the set of feasible sub-paths for the deterministic flow, andreceive, by the element from the sub-path determination agent, an actionsignal indicative of the selected sub-path for the deterministic flow.In at least some example embodiments, the response includes, for theselected sub-path for the deterministic flow, an indication of one ormore interfaces, of one or more nodes, scheduled to support the selectedsub-path for the deterministic flow. In at least some exampleembodiments, the response includes, for the selected sub-path for thedeterministic flow, deterministic resource allocation informationindicative of a set of deterministic resources to be allocated at one ormore nodes for supporting the deterministic flow. In at least someexample embodiments, the request is received from a node, and theresponse is sent toward the node. In at least some example embodiments,the request is received from a cluster leader of a cluster, and theresponse is sent toward the cluster leader of the cluster. In at leastsome example embodiments, the request is received from a controllerassociated with a cluster including the node, and the response is senttoward the controller associated with the cluster including the node. Inat least some example embodiments, the set of instructions is configuredto, when executed by the at least one processor, cause the apparatus toreceive, by the element, an indication that the selected sub-flow hasbeen released from the deterministic flow, determine, by the elementbased on a difference between an expected metric of the deterministicflow and an actual metric of the deterministic flow, a reward, andprovide, by the element to a sub-path determination agent supported bythe element, the reward.

In at least some example embodiments, a non-transitory computer-readablemedium stores a set of instructions configured to cause an apparatus toreceive, by an element of a communication network configured to supporta set of interfaces of a set of nodes of the communication network, arequest to resolve a routing request for a deterministic flow,determine, by the element based on state information for the set ofinterfaces, a selected sub-path for the deterministic flow, wherein thestate information includes scheduled sub-path information for a set ofscheduled deterministic flow sub-paths allocated on the set ofinterfaces and candidate sub-path information for a set of candidatedeterministic flow sub-paths requested on the set of interfaces, andsend, by the element, a response indicative of the selected sub-path forthe deterministic flow. In at least some example embodiments, thescheduled sub-path information includes, for each of the interfaces, anindication of a set of deterministic resources allocated over time onthe respective interface for the set of scheduled deterministic flowsub-paths. In at least some example embodiments, the candidate sub-pathinformation includes, for each of the interfaces, an indication of a setof deterministic resources requested over time on the respectiveinterface for the set of candidate deterministic flow sub-paths. In atleast some example embodiments, the set of candidate deterministic flowsub-paths includes a subset of candidate deterministic flow sub-pathsfrom a set of deterministic flow sub-path requests received by theelement, and the state information includes a sub-path backlog parameterconfigured to represent a remaining portion of the candidatedeterministic flow sub-paths from the set of deterministic flow sub-pathrequests received by the element. In at least some example embodiments,the state information includes at least one of latency requirementinformation or jitter requirement information. In at least some exampleembodiments, the state information includes at least one of a flowbacklog metric, a local key performance indicator, or a global keyperformance indicator. In at least some example embodiments, todetermine the selected sub-path for the deterministic flow, the set ofinstructions is configured to cause the apparatus to determine, by theelement based on a sub-path determination agent supported by theelement, a set of feasible sub-paths for the deterministic flow andselect, by the element from the set of feasible sub-paths for thedeterministic flow based on scoring of the set of feasible sub-paths forthe deterministic flow by the sub-path determination agent, the selectedsub-path for the deterministic flow. In at least some exampleembodiments, the sub-path determination agent is configured to determinethe set of feasible sub-paths based on a neural network. In at leastsome example embodiments, the neural network includes a set of internalelements trained based on historical information, and the set offeasible sub-paths is determined based on a set of internal parametersquantifying weights between internal elements. In at least some exampleembodiments, the sub-path determination agent is configured to determinethe set of feasible sub-paths based on a score calculator. In at leastsome example embodiments, the score calculator includes at least one ofa function configured to score sub-paths based on respective durationsof the sub-paths or a function configured to score sub-paths based onrespective alignments between the sub-paths and resource availability.In at least some example embodiments, to select the selected sub-pathfor the deterministic flow, the set of instructions is configured tocause the apparatus to receive a vector including, for each of thefeasible sub-paths in the set of feasible sub-paths, a recommendationidentifying the respective feasible sub-path and a score associated withthe respective feasible sub-path and select the selected sub-path basedon the scores associated with the feasible sub-paths. In at least someexample embodiments, the set of instructions is configured to cause theapparatus to send, by the element toward the sub-path determinationagent, a state update signal configured to update the state informationmaintained by the sub-path determination agent, initiate, by the elementtoward the sub-path determination agent, a pick signal configured torequest that the sub-path determination agent determine the set offeasible sub-paths for the deterministic flow, and receive, by theelement from the sub-path determination agent, an action signalindicative of the selected sub-path for the deterministic flow. In atleast some example embodiments, the response includes, for the selectedsub-path for the deterministic flow, an indication of one or moreinterfaces, of one or more nodes, scheduled to support the selectedsub-path for the deterministic flow. In at least some exampleembodiments, the response includes, for the selected sub-path for thedeterministic flow, deterministic resource allocation informationindicative of a set of deterministic resources to be allocated at one ormore nodes for supporting the deterministic flow. In at least someexample embodiments, the request is received from a node, and theresponse is sent toward the node. In at least some example embodiments,the request is received from a cluster leader of a cluster, and theresponse is sent toward the cluster leader of the cluster. In at leastsome example embodiments, the request is received from a controllerassociated with a cluster including the node, and the response is senttoward the controller associated with the cluster including the node. Inat least some example embodiments, the set of instructions is configuredto cause the apparatus to receive, by the element, an indication thatthe selected sub-flow has been released from the deterministic flow,determine, by the element based on a difference between an expectedmetric of the deterministic flow and an actual metric of thedeterministic flow, a reward, and provide, by the element to a sub-pathdetermination agent supported by the element, the reward.

In at least some example embodiments, a method includes receiving, by anelement of a communication network configured to support a set ofinterfaces of a set of nodes of the communication network, a request toresolve a routing request for a deterministic flow, determining, by theelement based on state information for the set of interfaces, a selectedsub-path for the deterministic flow, wherein the state informationincludes scheduled sub-path information for a set of scheduleddeterministic flow sub-paths allocated on the set of interfaces andcandidate sub-path information for a set of candidate deterministic flowsub-paths requested on the set of interfaces, and sending by theelement, a response indicative of the selected sub-path for thedeterministic flow. In at least some example embodiments, the scheduledsub-path information includes, for each of the interfaces, an indicationof a set of deterministic resources allocated over time on therespective interface for the set of scheduled deterministic flowsub-paths. In at least some example embodiments, the candidate sub-pathinformation includes, for each of the interfaces, an indication of a setof deterministic resources requested over time on the respectiveinterface for the set of candidate deterministic flow sub-paths. In atleast some example embodiments, the set of candidate deterministic flowsub-paths includes a subset of candidate deterministic flow sub-pathsfrom a set of deterministic flow sub-path requests received by theelement, and the state information includes a sub-path backlog parameterconfigured to represent a remaining portion of the candidatedeterministic flow sub-paths from the set of deterministic flow sub-pathrequests received by the element. In at least some example embodiments,the state information includes at least one of latency requirementinformation or jitter requirement information. In at least some exampleembodiments, the state information includes at least one of a flowbacklog metric, a local key performance indicator, or a global keyperformance indicator. In at least some example embodiments, determiningthe selected sub-path for the deterministic flow includes determining,by the element based on a sub-path determination agent supported by theelement, a set of feasible sub-paths for the deterministic flow andselecting, by the element from the set of feasible sub-paths for thedeterministic flow based on scoring of the set of feasible sub-paths forthe deterministic flow by the sub-path determination agent, the selectedsub-path for the deterministic flow. In at least some exampleembodiments, the sub-path determination agent is configured to determinethe set of feasible sub-paths based on a neural network. In at leastsome example embodiments, the neural network includes a set of internalelements trained based on historical information, and the set offeasible sub-paths is determined based on a set of internal parametersquantifying weights between internal elements. In at least some exampleembodiments, the sub-path determination agent is configured to determinethe set of feasible sub-paths based on a score calculator. In at leastsome example embodiments, the score calculator includes at least one ofa function configured to score sub-paths based on respective durationsof the sub-paths or a function configured to score sub-paths based onrespective alignments between the sub-paths and resource availability.In at least some example embodiments, selecting the selected sub-pathfor the deterministic flow includes receiving a vector including, foreach of the feasible sub-paths in the set of feasible sub-paths, arecommendation identifying the respective feasible sub-path and a scoreassociated with the respective feasible sub-path and selecting theselected sub-path based on the scores associated with the feasiblesub-paths. In at least some example embodiments, the method includessending, by the element toward the sub-path determination agent, a stateupdate signal configured to update the state information maintained bythe sub-path determination agent, initiating, by the element toward thesub-path determination agent, a pick signal configured to request thatthe sub-path determination agent determine the set of feasible sub-pathsfor the deterministic flow, and receiving, by the element from thesub-path determination agent, an action signal indicative of theselected sub-path for the deterministic flow. In at least some exampleembodiments, the response includes, for the selected sub-path for thedeterministic flow, an indication of one or more interfaces, of one ormore nodes, scheduled to support the selected sub-path for thedeterministic flow. In at least some example embodiments, the responseincludes, for the selected sub-path for the deterministic flow,deterministic resource allocation information indicative of a set ofdeterministic resources to be allocated at one or more nodes forsupporting the deterministic flow. In at least some example embodiments,the request is received from a node, and the response is sent toward thenode. In at least some example embodiments, the request is received froma cluster leader of a cluster, and the response is sent toward thecluster leader of the cluster. In at least some example embodiments, therequest is received from a controller associated with a clusterincluding the node, and the response is sent toward the controllerassociated with the cluster including the node. In at least some exampleembodiments, the method includes receiving, by the element, anindication that the selected sub-flow has been released from thedeterministic flow, determining, by the element based on a differencebetween an expected metric of the deterministic flow and an actualmetric of the deterministic flow, a reward, and providing, by theelement to a sub-path determination agent supported by the element, thereward.

In at least some example embodiments, an apparatus includes means forreceiving, by an element of a communication network configured tosupport a set of interfaces of a set of nodes of the communicationnetwork, a request to resolve a routing request for a deterministicflow, means for determining, by the element based on state informationfor the set of interfaces, a selected sub-path for the deterministicflow, wherein the state information includes scheduled sub-pathinformation for a set of scheduled deterministic flow sub-pathsallocated on the set of interfaces and candidate sub-path informationfor a set of candidate deterministic flow sub-paths requested on the setof interfaces, and means for sending by the element, a responseindicative of the selected sub-path for the deterministic flow. In atleast some example embodiments, the scheduled sub-path informationincludes, for each of the interfaces, an indication of a set ofdeterministic resources allocated over time on the respective interfacefor the set of scheduled deterministic flow sub-paths. In at least someexample embodiments, the candidate sub-path information includes, foreach of the interfaces, an indication of a set of deterministicresources requested over time on the respective interface for the set ofcandidate deterministic flow sub-paths. In at least some exampleembodiments, the set of candidate deterministic flow sub-paths includesa subset of candidate deterministic flow sub-paths from a set ofdeterministic flow sub-path requests received by the element, and thestate information includes a sub-path backlog parameter configured torepresent a remaining portion of the candidate deterministic flowsub-paths from the set of deterministic flow sub-path requests receivedby the element. In at least some example embodiments, the stateinformation includes at least one of latency requirement information orjitter requirement information. In at least some example embodiments,the state information includes at least one of a flow backlog metric, alocal key performance indicator, or a global key performance indicator.In at least some example embodiments, the means for determining theselected sub-path for the deterministic flow includes means fordetermining, by the element based on a sub-path determination agentsupported by the element, a set of feasible sub-paths for thedeterministic flow and means for selecting, by the element from the setof feasible sub-paths for the deterministic flow based on scoring of theset of feasible sub-paths for the deterministic flow by the sub-pathdetermination agent, the selected sub-path for the deterministic flow.In at least some example embodiments, the sub-path determination agentis configured to determine the set of feasible sub-paths based on aneural network. In at least some example embodiments, the neural networkincludes a set of internal elements trained based on historicalinformation, and the set of feasible sub-paths is determined based on aset of internal parameters quantifying weights between internalelements. In at least some example embodiments, the sub-pathdetermination agent is configured to determine the set of feasiblesub-paths based on a score calculator. In at least some exampleembodiments, the score calculator includes at least one of a functionconfigured to score sub-paths based on respective durations of thesub-paths or a function configured to score sub-paths based onrespective alignments between the sub-paths and resource availability.In at least some example embodiments, the means for selecting theselected sub-path for the deterministic flow includes means forreceiving a vector including, for each of the feasible sub-paths in theset of feasible sub-paths, a recommendation identifying the respectivefeasible sub-path and a score associated with the respective feasiblesub-path and means for selecting the selected sub-path based on thescores associated with the feasible sub-paths. In at least some exampleembodiments, the apparatus includes means for sending, by the elementtoward the sub-path determination agent, a state update signalconfigured to update the state information maintained by the sub-pathdetermination agent, means for initiating, by the element toward thesub-path determination agent, a pick signal configured to request thatthe sub-path determination agent determine the set of feasible sub-pathsfor the deterministic flow, and means for receiving, by the element fromthe sub-path determination agent, an action signal indicative of theselected sub-path for the deterministic flow. In at least some exampleembodiments, the response includes, for the selected sub-path for thedeterministic flow, an indication of one or more interfaces, of one ormore nodes, scheduled to support the selected sub-path for thedeterministic flow. In at least some example embodiments, the responseincludes, for the selected sub-path for the deterministic flow,deterministic resource allocation information indicative of a set ofdeterministic resources to be allocated at one or more nodes forsupporting the deterministic flow. In at least some example embodiments,the request is received from a node, and the response is sent toward thenode. In at least some example embodiments, the request is received froma cluster leader of a cluster, and the response is sent toward thecluster leader of the cluster. In at least some example embodiments, therequest is received from a controller associated with a clusterincluding the node, and the response is sent toward the controllerassociated with the cluster including the node. In at least some exampleembodiments, the apparatus includes means for receiving, by the element,an indication that the selected sub-flow has been released from thedeterministic flow, means for determining, by the element based on adifference between an expected metric of the deterministic flow and anactual metric of the deterministic flow, a reward, and means forproviding, by the element to a sub-path determination agent supported bythe element, the reward.

In at least some example embodiments, an apparatus includes at least oneprocessor and at least one memory including a set of instructions,wherein the set of instructions is configured to, when executed by theat least one processor, cause the apparatus to receive, by a clusterleader of a cluster of nodes of a multi-tier communication network, arequest for a path for a deterministic flow, determine, by the clusterleader of the cluster of nodes, a set of deterministic resources to beallocated at one or more nodes of the cluster of nodes for supportingthe deterministic flow within the multi-tier communication network, andprovide, by the cluster leader of the cluster of nodes, a responseindicative of the set of deterministic resources to be allocated at oneor more nodes of the cluster of nodes for supporting the deterministicflow within the multi-tier communication network. In at least someexample embodiments, a non-transitory computer-readable medium stores aset of instructions configured to cause an apparatus to receive, by acluster leader of a cluster of nodes of a multi-tier communicationnetwork, a request for a path for a deterministic flow, determine, bythe cluster leader of the cluster of nodes, a set of deterministicresources to be allocated at one or more nodes of the cluster of nodesfor supporting the deterministic flow within the multi-tiercommunication network, and provide, by the cluster leader of the clusterof nodes, a response indicative of the set of deterministic resources tobe allocated at one or more nodes of the cluster of nodes for supportingthe deterministic flow within the multi-tier communication network. Inat least some example embodiments, a method includes receiving, by acluster leader of a cluster of nodes of a multi-tier communicationnetwork, a request for a path for a deterministic flow, determining, bythe cluster leader of the cluster of nodes, a set of deterministicresources to be allocated at one or more nodes of the cluster of nodesfor supporting the deterministic flow within the multi-tiercommunication network, and providing, by the cluster leader of thecluster of nodes, a response indicative of the set of deterministicresources to be allocated at one or more nodes of the cluster of nodesfor supporting the deterministic flow within the multi-tiercommunication network. In at least some example embodiments, anapparatus includes means for receiving, by a cluster leader of a clusterof nodes of a multi-tier communication network, a request for a path fora deterministic flow, means for determining, by the cluster leader ofthe cluster of nodes, a set of deterministic resources to be allocatedat one or more nodes of the cluster of nodes for supporting thedeterministic flow within the multi-tier communication network, andmeans for providing, by the cluster leader of the cluster of nodes, aresponse indicative of the set of deterministic resources to beallocated at one or more nodes of the cluster of nodes for supportingthe deterministic flow within the multi-tier communication network.

BRIEF DESCRIPTION OF THE DRAWINGS

The teachings herein can be readily understood by considering thefollowing detailed description in conjunction with the accompanyingdrawings, in which:

FIG. 1 depicts an example embodiment of a communication systemconfigured to support deterministic networking;

FIG. 2 depicts an example embodiment of multi-tier hierarchical networkconfigured to support deterministic networking;

FIG. 3 depicts an example embodiment of multi-tier hierarchical networkconfigured to support deterministic networking

FIG. 4 depicts an example embodiment of a method for supportingprovisioning of a deterministic flow in a multi-tier hierarchicalnetwork;

FIG. 5 depicts an example embodiment of a method for supportingprovisioning of a deterministic flow in a multi-tier hierarchicalnetwork;

FIG. 6 depicts an example embodiment of a communication systemconfigured to support deterministic networking reliability based on flowreplication and elimination;

FIG. 7 depicts an example embodiment of a method for supportingprovisioning of a deterministic flow in a multi-tier hierarchicalnetwork;

FIG. 8 depicts an example embodiment of a node including a pathrecommendation agent configured to determine a path for a deterministicflow;

FIG. 9 depicts an example embodiment of a state matrix providing a staterepresentation for deterministic flow scheduling;

FIG. 10 depicts an example embodiment of a method for supportingprovisioning of a deterministic flow in a multi-tier hierarchicalnetwork;

FIG. 11 depicts an example embodiment of a method for supportingprovisioning of a deterministic flow in a multi-tier hierarchicalnetwork;

FIG. 12 depicts an example embodiment of a node including a score-basedpath recommendation agent configured to determine a path for adeterministic flow;

FIG. 13 depicts an example embodiment of a state matrix providing astate representation for deterministic flow scheduling;

FIG. 14 depicts an example embodiment of a method for supportingprovisioning of a deterministic flow in a multi-tier hierarchicalnetwork;

FIG. 15 depicts an example embodiment of a method for supportingprovisioning of a deterministic flow in a multi-tier hierarchicalnetwork;

FIG. 16 depicts an example embodiment of a method for supportingprovisioning of a deterministic flow in a multi-tier hierarchicalnetwork

FIG. 17 depicts an example embodiment of a system configured to supportmulti-tier deterministic networking; and

FIG. 18 depicts an example embodiment of a computer suitable for use inperforming various functions presented herein.

To facilitate understanding, identical reference numerals have been usedherein, wherever possible, in order to designate identical elements thatare common among the various figures.

DETAILED DESCRIPTION

Various example embodiments for supporting multi-tier deterministicnetworking are presented. Various example embodiments for supportingmulti-tier deterministic networking may be configured to supportprovisioning of deterministic flows in multi-tier deterministicnetworking. Various example embodiments for supporting multi-tierdeterministic networking may be configured to support adaptivedeterministic routing in multi-tier deterministic networks. Variousexample embodiments for supporting multi-tier deterministic networkingmay be configured to support score-based deterministic routing inmulti-tier deterministic networks. Various example embodiments forsupporting multi-tier deterministic networking may be configured tosupport adaptive deterministic routing and/or score-based deterministicrouting in multi-tier deterministic networks based on analysis of astate representation for path and/or sub-path selection in multi-tierdeterministic networks. Various example embodiments for supportingmulti-tier deterministic networking may be configured to supporthierarchical resource allocation and deallocation in multi-tierdeterministic networking, optimal route finding in multi-tierdeterministic networking, or the like, as well as various combinationsthereof. Various example embodiments for supporting multi-tierdeterministic networking may be configured to support multi-tierdeterministic networking which may be based on various deterministicnetworking capabilities (e.g., Institute of Electrical and ElectronicsEngineers (IEEE) Time-Sensitive Networking (TSN), Internet EngineeringTask Force (IETF) Deterministic Networking (DetNet), or the like).Various example embodiments for supporting multi-tier deterministicnetworking may be configured to support multi-tier deterministicnetworking that may be based on various network topologies. Variousexample embodiments for supporting multi-tier deterministic networkingmay be configured to support multi-tier deterministic networking thatmay be applied in various contexts for ensuring bounded performance forvarious metrics (e.g., supporting autonomous vehicles, factoryautomation, communication at mining sites, or the like). It will beappreciated that these as well as various other example embodiments, andassociated advantages or potential advantages, may be further understoodby first considering a communication system that is configured tosupport multi-tier deterministic networking.

FIG. 1 depicts an example embodiment of a communication systemconfigured to support deterministic networking.

The communication system 100 includes a communication network 110 and anetwork controller 120. The communication network 110 including a set ofnodes 111 and a set of communication links 112. It is noted that, forease of reference, the nodes 111 are labeled using letters as follows:A, B, C, D, E, F, H, J, K, L, M, and N. The communication network 110may be a physical network or a virtual network and, thus, the nodes 111may include physical nodes or virtual nodes (or a combination thereof).The communication network 110 may be configured to supportnon-deterministic communications and deterministic communications. Thenodes 111 may include various types of nodes which may be configured tosupport non-deterministic and/or deterministic communications, such asrouters, switches, or the like, as well as various combinations thereof.The links 112 may include various types of communication links which maysupport communications between the nodes 111. The network controller 120is configured to provide various control functions for the communicationnetwork 110 (e.g., network provisioning functions, network monitoringfunctions, or the like, as well as various combinations thereof. It willbe appreciated that the communication network 110, although primarilypresented with respect to specific types, numbers, and arrangements ofnodes 111 and links 112, may include various other types, numbers,and/or arrangements of nodes 111 and links 112.

The communication network 110 is configured to support deterministiccommunications. The communication network 110 may be configured tosupport deterministic communications based on deterministic networking.The deterministic networking may be configured to support boundedperformance guarantees based on various performance measures (e.g.,latency, jitter, or the like, as well as various combinations thereof).The deterministic communications may be based on IEEE TSN, IETF DetNet,or the like, as well as various combinations thereof. For example,various example embodiments may be configured to be compliant with andprovide extensions to such deterministic communications capabilities,support extension of such deterministic communications capabilities tomore general settings, and various other use cases which also mayinclude support for broader deployment of deterministic networking. Forexample, various example embodiments may be configured to supportsignaling and control mechanisms that allow control and data planes ofdeterministic flows to integrate into existing deterministic networksthat are based on such deterministic communications capabilities. Forexample, various example embodiments may be configured to supportmulti-tier deterministic networking where both IEEE TSN and IETF DetNetare used to support deterministic networking, such as where IEEE TSN isused for lower layers of the network protocol stack (e.g., Layers 1-2)and IETF DetNet is used for higher layers of the network protocol stack(e.g., Layers 2-3).

The communication network 110 includes a deterministic flow 119 that isestablished through nodes A↔F↔K↔M↔N. The deterministic flow 119 may beconfigured to support bounded performance guarantees (e.g., latency,jitter, reliability, or the like, as well as various combinationsthereof). The deterministic flow 119 may be established in various ways.The deterministic flow 119 may be established based on one or moredeterministic networking standards. For example, using DetNet, thedeterministic flow 119 may be established by performing anyconfiguration needed by the DetNet transit nodes in the network for theclass(es) of service to be provided (including one or more classes ofDetNet service), computing the resource requirements of the new DetNetflow (e.g., in terms of required bandwidth and other types ofresources), finding the path that the DetNet flow will take through thenetwork from the source to the destination (point-to-point) ordestinations (point-to-multipoint), computing the worst-case end-to-endlatency for the DetNet flow, determining whether sufficient resourcesare available for that flow to guarantee the required latency and toprovide zero congestion loss, and committing resources to the flow(e.g., which may or may not include adjusting the parameters thatcontrol the filtering and/or queuing mechanisms at each hop along thepath of the DetNet flow). The deterministic flow 119 may be establishedbased on clustering of the communication network 110 to form amulti-tier hierarchical network, as discussed further herein withrespect to FIG. 2 and FIG. 3 . It will be appreciated that use of amulti-tier hierarchical network to support establishment ofdeterministic flows may be further understood by first consideringvarious example embodiments for clustering communications networks toform multi-tier deterministic networks.

Various example embodiments for supporting multi-tier deterministicnetworking are presented. In a given multi-tier hierarchical network,allocation of deterministic resources in the multi-tier hierarchicalnetwork may be supported. In a given multi-tier hierarchical network,hierarchical deterministic flow provisioning and initiation may betailored based on use of clustering for the multi-tier hierarchicalnetwork. In a given multi-tier hierarchical network, each node (e.g.,router) that is configured to support allocation of deterministicresources may be configured to operate according to a role and using ahierarchical coordination protocol that is configured to maintain abalance between centralized and decentralized operation, therebyenabling determinism to be applied to larger geographic areas wherevarious deterministic measures (e.g., latency, jitter, or the like) maybe applied for various purposes (e.g., applications, services, or thelike). These and various other example embodiments for supportingallocation of deterministic resources in multi-tier hierarchicalnetworks may be further understood by considering the followingcommunication network.

The communication network, which may be either physical or virtual,includes N communication nodes connected via unidirectionalcommunication links. The representation of this network may be given bya directed graph

=(

,

), where

includes the set of nodes and

includes available links (e.g., unidirectional links between the nodes).The network is configured to provide deterministic communicationservices to various customers (e.g., industrial customers, end-usersapplications, and so forth) for various use cases (e.g., factories,mining sites, remote surgery, concert areas, low latency financialservices, or the like). The nodes in the network are capable of routingtheir own packets or intermediate packets using various routingtechniques (e.g., segment routing, source routing, or the like, as wellas various combinations thereof) over protocol stacks which may supportvarious types of protocols (e.g., IP, MPLS, or the like, as well asvarious combinations thereof). The protocol stacks also may supportdeterministic communication guarantees for various parameters (e.g.,latency, jitter, reliability, or the like, as well as variouscombinations thereof) based on various technologies configured tosupport such deterministic communication guarantees (e.g., IETF DetNet,IEEE TSN, communication stacks that are capable of supportingdeterministic communication guarantees, or the like, as well as variouscombinations thereof). It will be appreciated that, although primarilypresented with respect to use of a unidirectional links and a directedgraph, various example embodiments for supporting multi-tierdeterministic networking also may be applied for bidirectional links,undirected graphs, or the like, as well as various combinations thereof.

The communication network is formed into K tiers with each tier khierarchically forming C_(k) number of non-overlapping clusters of nodesor parent clusters (if defined), which may be performed eitherstatically or automatically according to a clustering mechanism. Moreprecisely, for the highest tier k=1 with C_(k) clusters whose nodes areassigned, the process keeps repeating for sub-tiers k+1, k+2, . . . , K,each time a given cluster of tier k forms sub-clusters from existingnodes of that cluster at tier k. The whole process results in amulti-tier hierarchical clustered network, whose aim to achievedeterministic performance with a balance betweencentralized-decentralized administration and computation-communicationcomplexity. In such a network, one can observe that the highest tier(i.e., k=1) has fewer or equal number of clusters compared to lowertiers, such as C₁≤C₂≤ . . . ≤C_(K). The nodes in the network haveknowledge of their clusters for each tier. The network operator mightopt to choose (or not to choose), either statically or algorithmically,to form clusters in a given tier, if the number of nodes in that tier islower than a predefined threshold. In the lowest tier (i.e., k=K), itmay be assumed that each cluster has a designated cluster leader (whichalso may be referred to as a group leader) that is in charge of coldstart of nodes within the cluster, and handles some part of controlplane procedures required in its cluster at the lowest tier. Thedesignated cluster leader can be assigned by a central or local entity,either statically or autonomously (using statistical tools and machinelearning techniques), based on some design metrics and negotiationprocess. The cluster leaders may be connected to SDN controllers (e.g.,for signaling, bootstrapping, control messaging, or the like, as well asvarious combinations thereof), which in turn may be connected to otherSDN controllers in a hierarchical manner until reaching the top networkcontroller.

It is noted that various aspects of such multi-tier hierarchicaldeterministic networks may be further understood by considering theexamples of FIG. 2 and FIG. 3 .

FIG. 2 depicts an example embodiment of multi-tier hierarchical networkconfigured to support deterministic networking.

In FIG. 2 , the multi-tier hierarchical network 200 includes a set ofnodes 211 interconnected by a set of links 212. The nodes 211 arelabeled as nodes A, B, C, D, E, F, H, J, K, L, M, and N for ease ofreference. The nodes 211, as illustrated in FIG. 2 , have been organizedinto clusters in two tiers (K=2) to form a multi-tier hierarchicaldeterministic network. The lower tier, denoted as Tier 2, includes fourclusters as follows: (1) a first cluster including nodes A, B, and Cwith node B operating as the cluster leader, (2) a second clusterincluding nodes D, E, and F with node D operating as the cluster leader,(3) a third cluster including nodes H, J, and K with node K operating asthe cluster leader, and (4) a fourth cluster including nodes L, M, and Nwith node M operating as the cluster leader. The upper tier, denoted asTier 1, includes two clusters, each of which includes two of the Tier 2clusters as sub-clusters as follows: (1) the first Tier 1 clusterincludes the [A, B, C] and [D, E, F] clusters as sub-clusters and has anetwork controller (denoted as Tier 1 Network Controller 1) as itsleader and (2) the second Tier 1 cluster includes the [H, J, K] and [L,M, N] clusters as sub-clusters and has a network controller (denoted asTier 1 Network Controller 2) as its leader. The Tier 1 NetworkControllers are controlled by a Top Network Controller, such that theTop Network Controller is capable of controlling any of the nodes 211 inthe multi-tier hierarchical network 200. It will be appreciated that,although primarily presented with respect to a multi-tier hierarchicaldeterministic network having a specific number of hierarchical levels,the multi-tier hierarchical deterministic network may have any suitablenumber of hierarchical levels.

In FIG. 2 , the multi-tier hierarchical network 200 supportsdeterministic networking. The deterministic networking may be based onone or more deterministic networking standards, such as IEEE TSN, IETFDetNet, or the like. The deterministic networking may be configured toprovide deterministic services of bounded latency and zero congestionloss by configuring and allocating network resources for exclusive useof deterministic flows, providing or finding (in the data plane) theresources to be exploited by any given packet, and characterizing thebehavior of those resources (e.g., transmission queue selection) so thatlatency and reliability bounds can be assured. The deterministicnetworking standards may include various types of standards, such astime synchronization standards (e.g., IEEE 802.1AS, IEEE 1588, or thelike), high reliability (e.g., IEEE P802.1CB, IEEE 802.1Qca, IEEE802.1Qci, P802.1AS-Rev, or the like), bounded latency (e.g., IEEE802.1Qav, IEEE 802.1Qbu, IEEE 802.1Qbv, IEEE 802.1Qch, IEEE 802.1Qcr, orthe like), data resources and APIs (e.g., IEEE 802.1Qat, IEEE 802.1Qcc,IEEE 802.1Qcp, IEEE 802.1CS, or the like), or the like, as well asvarious combinations thereof. In FIG. 2 , an example of a deterministicflow 219, going through the path of A N, also is illustrated.

It will be appreciated that use of clustering to form the multi-tierhierarchical network 200 of FIG. 2 may be further understood by way ofreference to FIG. 3 .

It will be appreciated, that although primarily presented with respectto supporting deterministic networking in a particular type ofcommunication network (e.g., a network having specific types, numbers,and arrangements of nodes organized in a multi-tier hierarchicalmanner), deterministic networking may be supported in various othertypes of communication networks (e.g., networks having other types,numbers, and/or arrangements of nodes, networks that are nothierarchical or that are hierarchical with other numbers of hierarchicallevels, or the like, as well as various combinations thereof).

FIG. 3 depicts an example embodiment of multi-tier hierarchical networkconfigured to support deterministic networking.

The multi-tier communication network 300 is similar to the multi-tiercommunication network 200 of FIG. 2 (illustratively, including the samearrangement of nodes, links, and controllers).

In the multi-tier communication network 300, assume that every node andcluster is associated with a “relative” identification number, which isunique only within the cluster (for nodes) and respective tier (forclusters) and is assigned manually or automatically by a distributionmechanism. An example of this distribution is illustrated in FIG. 3 ,where relative numbers of nodes and clusters are given in parentheses(.) and brackets [.], respectively.

In the multi-tier communication network 300, further assume that eachnode can also be identified with an “absolute” identification number,which is unique within the the multi-tier communication network 300 andis composed of a concatenation of its relative number and hierarchicalcombination of all relative identification numbers of associatedclusters.

The relative identification number and absolute identification numbermay be further understood by considering an example associated with NodeA in FIG. 3 . In FIG. 3 , for example, Node A has a relativeidentification number of (2), with its lowest tiered cluster numbered as[1] and its upper tier cluster numbered as [1], thereby forming anabsolute identification number from highest tier to lowest tier entitiesthat is represented in the vector of (1, 1, 2). In the case of clusteridentification, for example, the local cluster to which Node A belongsat the lowest tier has a relative identification number of [1] and anabsolute identification number vector of [1, 1]. This absoluteidentification number of that cluster is unique as it represents, fromright to left, its own relative identification and the relativeidentification of its parent cluster [1].

With respect to identification numbers it is noted that, by default(e.g., unless gathered externally for communication needs), each nodehas only the knowledge of its identification numbers, neighbor nodes inits lowest tier cluster, and its leader node. Meanwhile, group/clusterleader nodes and SDN controllers can store and track relative andabsolute identification numbers and links of entities within theirrespective tier and cluster (not necessarily all the entities lower inthe hierarchy, if such entities exist) and can communicate with theirdesignated controllers. Such a hierarchical relative/absoluteidentification number distribution is aimed to avoid or minimizecommunication and tracking complexity in large clustered networks, aswell as enabling the proposed mechanism to function properly in theclustered networks. As for the example given in the figure, thefollowing may be seen:

(1) The Top Network Controller has control over Tier 1 NetworkController 1 and Tier 1 Network Controller 2 at tier k=1, and is awarethat these controllers are in charge of clusters [1] and [2],respectively. The Top Network Controller is also aware of inter-clusterlinks [1]E↔H[2] and [1]F↔K[2] with absolute identifiers of correspondingnodes E, H, F, and F. The link notation, for example [1]E↔H[2], meansthat the link between clusters [1] and [2] exists via nodes E and H.Multiple inter-cluster links could exist between two nodes; however, forease of notation and without loss of generality, the example containsonly a single link between two nodes.

(2) The Tier 1 Network Controller 1 has control over group leader nodesB and D at tier k=2, and is aware that these group leaders are in chargeof clusters [1, 1] and [1, 2], respectively. The inter-cluster links [1,1]C↔D[1,2] and [1,1]A↔F[1,2] are also tracked.

(3) The Tier 1 Network Controller 2 has control over group leader nodesK and M at tier k=2, and is aware that these group leaders are in chargeof clusters [2, 2] and [2, 1], respectively. The inter-cluster links[2,2]K↔M[2,1] and [2,2]J↔L[2,1] are also tracked.

(4) The Tier 2 Group Leaders are in charge of their nodes in theclusters of the lowest tier. They have knowledge of links between thenodes in the cluster, with the purpose of finding any local path withinthe cluster, for a given path-finding mechanism. For example, groupleader Node B has knowledge of intra-cluster links [1,1]A↔B[1,1],[1,1]B↔C[1,1] and [1,1]C↔A[1,1].

(5) The nodes have knowledge of their own relative and absoluteidentifiers, and know how to reach out to group leader.

It will be appreciated, that although primarily presented with respectto supporting deterministic networking in a particular type ofmulti-tier communication network (e.g., a multi-tier communicationnetwork having specific numbers and arrangements clusters and tiers),deterministic networking may be supported in various other types ofmulti-tier communication network (e.g., networks having other numbersand/or arrangements of clusters, networks having other numbers and/orarrangements of tiers, or the like, as well as various combinationsthereof).

FIG. 4 depicts an example embodiment of a method for supportingprovisioning of a deterministic flow in a multi-tier hierarchicalnetwork. For purposes of clarity, the method 400 is primarily describedwithin the context of an example based on FIG. 3 in which node A wishesto communicate to node N using a deterministic flow.

At block 405, the source node x sends a flow request to its clusterleader g_(x) for deterministic communication. For example, the sourceNode A sends its intention to its group leader, Node B, providing theabsolute identification vector of destination Node N. From block 405,the method 400 proceeds to block 410.

At block 410, the designated group leader g_(x) determines whether ornot the flow request can be resolved locally in the cluster. The groupleader node B, having both absolute identification vectors of nodes Aand N, say (1,1,2) and (2,1,2) respectively, compares these vectors fromright to left (from lowest tier to highest tier) and identifies that thefirst index in these vectors differs, i.e., (1,1,2)⇔(2,1,2) whereitalicized numbers represent the found index i=2 (note that indicesstart with 0). The found index i is inversely proportional to the tiernumber in which related pointed cluster has enough global knowledge toresolve the request, i.e., the tier in charge of resolving the requestis k=K−i and the related cluster is C_(k). If the index is i=0 (which isnot the case in this example) it would represent the fact the requestcan be resolved locally with the group leader and, thus, the method 400would proceed to block 415. If the index i>0 (which is the case in thisexample), it would represent the fact the request cannot be resolvedlocally with the group leader and, thus, the method 400 would proceed toblock 425.

At block 415, the source node x, the relay nodes, and the destinationnode(s) receive configuration and final allocation/unallocationdecisions from their respective group leader(s). The nodes that arereceiving the results of requests perform allocation or unallocation ofresources (e.g., bandwidth, time slots, or the like) by triggeringrelated deterministic protocol stacks (e.g., IEEE TSN, IETF DetNet, orthe like) and respond with the results of the requested allocation orunallocation actions. From block 415, the method 400 proceeds to block420.

At block 420, the source node x, the relay nodes, and the destinationnode(s) start/stop the deterministic flow communication. In the case ofstarting deterministic flow communication, the communication continuesuntil further notice by the network controllers. In case of stoppingdeterministic flow communication, the related deterministic protocolstack in the node then is triggered to release the resources.

At block 425, the designated group leader forwards the request to itsnearest “differentiating” controller c_(x) responsible for tier k. Inthe example, since the identifier comparison from block 410 yielded i=2,therefore k=K−i=2−2=0 and, thus, the differentiating controller is theTop Network Controller and the designated group leader forwards therequest to related controller. From block 425, the method 400 proceedsto block 430.

At block 430, the intended controller queries feasible inter-clusterpaths and intra-cluster paths within sub-controllers (or neighbor groupleaders depending on the topology), resulting in recursive queriesinitiated by controllers. In the example, provided that the top networkcontroller received the request from respective group leader, having thesource and destination vectors for Node A (1,1,2) and Node N (2,1,2),the following four operations would expected to take place in anasynchronous fashion:

Operation 1: For path A N between Node A (1,1,2) and Node N (2,1,2), thetop tier controller checks existence of inter-cluster links (orsub-paths) connecting cluster [1] and [2] by executing a path findingmechanism, and among the feasible solutions, it picks one solutionfollowing a criteria (e.g., minimum hops, minimum cost with cost being afunction of delay and throughput, or the like). Assume that theinter-cluster link [1]F↔K[2] is selected in the example. Given that morepaths need to be resolved between nodes A↔ . . . ↔F and nodes K↔ . . .↔N as result of vector comparison similar to earlier stages, the topcontroller launches a path resolution request, this time requesting A↔ .. . ↔F from Tier 1 Network Controller 1 and requesting K↔ . . . ↔N fromTier 1 Network Controller 2.

Operation 2: Tier 1 Network Controller 1 checks out A↔ . . . ↔F betweennodes A and F, resolves inter-cluster paths at its tier, and picks asolution (say [1, 1] A↔F [1, 2]). As absolute identifiers of both node A(1, 1, 2) and node F (1, 2, 3) for the link are known and the index i=1is pointing out to this controller, there is no more need of recursiverequests that could be potentially forwarded to group leaders in thebottom tiers. The result is forwarded to the top controller.

Operation 3: Tier 1 Network Controller 2 checks out K↔ . . . ↔N betweennodes K an N, resolves inter-cluster paths at its tier, and picks asolution (say [2, 2] K↔M [2, 1]). Similar to Operation 2 above, there isno need of additional requests for resolving K↔M, however, for M↔ . . .↔N, group leader M receives a request from the controller to resolve thepath M↔ . . . ↔N. When all results are resolved, they are forwarded tothe top controller.

Operation 4: The group leader M, having both absolute identifiers ofnode M and node N, performs a comparison and figures out that thesolution can be found locally. It triggers a path computation mechanismand, among feasible solutions, it picks [2,1]M↔N [2, 1]. The result isforwarded back to requesting controller.

It is noted that, from block 430, the method 400 proceeds to block 435for determining whether all of the associated responses have beenreceived based on the recursive queries.

At block 435, a determination is made as to whether all query resultshave been received by the “differentiating” controller. The controllerdetermines whether all recursive requests from its lower tiercontrollers are returned or not. If all query results have been receivedby the differentiating controller, then the method 400 proceeds to block440, otherwise the method 400 proceeds to block 445.

At block 440, all query results are compiled to determine whether or notthe flow request is resolvable. The “differentiating” controllerpromotes the decision to sub-controllers. As an example, feasiblelink/sub-path solutions from Operation 4 (namely, M↔N), Operation 3(namely K↔M), Operation 2 (namely K↔M and A↔F), and Operation 1 (namelyF↔K) are compiled. The final path, which is A↔F↔K↔M↔N, is feasible and,thus, is promoted to sub-controllers of the path. It is noted that, ifthere is no feasible solution, this also would be promoted. From block440, the method 400 proceeds to block 415.

At block 445, a determination is made as to whether a timeout hasoccurred. The determination may be made based on a predefined timeoutthreshold. If a timeout has occurred, the method 400 returns to block440, otherwise the method 400 proceeds to block 450.

At block 450, the controller waits until the query results arrive or apredefined time duration. From block 450, the method 400 returns toblock 435, where a determination is again made as to whether all queryresults have been received by the “differentiating” controller. Themethod 400 continues in this manner until all query results have beenreceived by the “differentiating” controller (block 435) or until atimeout is detected (block 445), at which time all query results arecompiled to determine whether or not the flow request is resolvable(block 440).

FIG. 5 depicts an example embodiment of a method for supportingprovisioning of a deterministic flow in a multi-tier hierarchicalnetwork. It will be appreciated that although primarily presented asbeing performed serially, at least a portion of the blocks of method 500may be performed contemporaneously or in a different order than aspresented in FIG. 5 .

It will be appreciated that the manner in which the blocks of method 500are performed may depend on which element of the multi-tier hierarchicalnetwork is performing the functions (e.g., a node that is operating as acluster leader in the lowest tier, a node or controller operating as acluster leader and at a tier above the lowest tier, or the like as wellas various combinations thereof).

It will be appreciated that various functions of method 400 of FIG. 4may be performed within the context of the method 500 of FIG. 5depending on which element of the multi-tier hierarchical network isperforming the functions (e.g., a node that is operating as a clusterleader in the lowest tier, a node or controller operating as a clusterleader and at a tier above the lowest tier, or the like as well asvarious combinations thereof).

At block 501, the method 500 begins.

At block 510, receive, by a cluster leader of a cluster of nodes of amulti-tier communication network, a request for a path for adeterministic flow.

The cluster of nodes may be at any tier of the multi-tier communicationnetwork. For example, the cluster of nodes may be at the lowest tier, inwhich case the request may be received by a node of the cluster that isoperating as a cluster leader for the cluster and may be received from asource of the deterministic flow or another node of the cluster onbehalf of the source of the deterministic flow. For example, the clusterof nodes may be at a next-to-lowest tier, in which case the request maybe received by node of a cluster of the next-to-lowest tier that isoperating as a cluster leader for the cluster of the next-to-lowest tieror from a controller that is operating as a cluster leader for thecluster of the next-to-lowest tier (e.g., a Tier 1 Network Controller orother controller), may be received from a cluster leader of a cluster ofthe lowest tier, may be received based on a determination by the clusterleader of the cluster of the lowest tier that the request for the pathfor the deterministic flow cannot be resolved within the cluster of thelowest tier, and so forth.

The request for the path for the deterministic flow may be a request forthe end-to-end path for the deterministic flow (e.g., when received bythe cluster leader of the cluster of nodes from the source of thedeterministic flow), a request for a sub-path forming a portion of theend-to-end path (e.g., an intra-cluster sub-path, an inter-clustersub-path, or the like, as well as various combinations thereof) for thedeterministic flow (e.g., when received by a cluster leader of a clusterat a tier above the lowest tier such that the end-to-end path may spanmultiple clusters at one or more hierarchical layers of the multi-tiercommunication network), or the like.

At block 520, determine, by the cluster leader of the cluster of nodes,a set of deterministic resources to be allocated at one or more nodes ofthe cluster of nodes for supporting the deterministic flow within themulti-tier communication network.

The set of deterministic resources to be allocated at one or more nodesof the cluster of nodes for supporting the deterministic flow within themulti-tier communication network may be determined by the cluster leaderof the cluster of nodes locally. This may be the case where the clusterleader determines that the end-to-end path or relevant portion of theend-to-end can be resolved locally within the cluster without a need forrecursive propagation of requests to a cluster leader at a next-highertier of the multitier communication network.

The set of deterministic resources to be allocated at one or more nodesof the cluster of nodes for supporting the deterministic flow within themulti-tier communication network may be determined by the cluster leaderof the cluster of nodes based on propagation of a request to a clusterleader at a next-higher tier of the multitier communication network andreceipt of an associated response from the cluster leader at thenext-higher tier of the multitier communication network. It will beappreciated that the response from the cluster leader at the next-highertier of the multitier communication network may be based on recursiverequests and responses by and to, respectively, cluster leaders at evenhigher tiers of the multi-tier communication network until reaching atier with visibility to the end-to-end path for the deterministic flow.

The set of deterministic resources may include various types ofdeterministic resources which may be allocated at nodes for supporting adeterministic flow (e.g., bandwidth, time slots, or the like, as well asvarious combinations thereof).

At block 530, provide, by the cluster leader of the cluster of nodes, aresponse indicative of the set of deterministic resources to beallocated at one or more nodes of the cluster of nodes for supportingthe deterministic flow within the multi-tier communication network. Theresponse may be provided to one or more nodes of the end-to-end path forthe deterministic flow (e.g., where the cluster leader of the cluster ofnodes is associated with the cluster at the lowest tier of themulti-tier communication network), one or more cluster leaders of one ormore clusters at a next-lower tier of multi-tier communication network(e.g., where the cluster leader is a node or controller operating at atier above the lowest tier of the multi-tier communication network)which may then in turn send associated responses to one or more clusterleaders of one or more clusters at the lowest tier of the multitiercommunication network, and so forth. In this manner, responses may berecursively delivered from cluster leaders higher in the multi-tiercommunication network to cluster leaders lower in the multi-tiercommunication network until each of the nodes of the end-to-end path ofthe deterministic flow (namely, the source node, one or more relaynodes, and one or more destination nodes) is informed of thedeterministic resources to be allocated for the deterministic flow. Thenodes of the end-to-and path of the deterministic flow may allocatedeterministic resources for the deterministic flow by triggering thedeterministic protocol stacks in the nodes to allocate the deterministicresources for the deterministic flow.

At block 599, the method 500 ends.

Various example embodiments for supporting multi-tier deterministicnetworking may provide various advantages or potential advantages. Forexample, various example embodiments for supporting multi-tierdeterministic networking may be configured to support handling ofresources in a manner configured to support procedures and interfacingin deterministic communications such as IEEE TSN and IETF DetNet. Forexample, various example embodiments for supporting multi-tierdeterministic networking may be configured to construct a hierarchicalfederated mechanism, instead of fully centralized or decentralizedapproaches, making it possible to scale the solution without dramaticloss in network performance. For example, various example embodimentsfor supporting multi-tier deterministic networking may be configured toenable hierarchical clustered topologies to be mapped as hierarchicallatency zones of the network, thereby providing support fordeterministic communications in edge and central clouds. For example,various example embodiments for supporting multi-tier deterministicnetworking may be configured to enable partial (and dynamic)construction of a path/sub-path of a deterministic flow, as well assource routing methods and federation for the final path, that canprovide a substantial advantage over traditional methods in terms ofconfiguration and scalability. For example, various example embodimentsfor supporting multi-tier deterministic networking may be configured tosupport flow allocation (and routing) in networks, including large-scalenetworks, for deterministic communications. For example, various exampleembodiments for supporting multi-tier deterministic networking, bysupporting balance between centralized and decentralized networkoperation, may be configured to overcome various deficiencies associatedwith centralized network operation (e.g., where a large number of nodesin the network, if not handled properly, may cause scalability issuesand performance degradation, due to centralized high-complexityallocation mechanisms) and various deficiencies associated withdecentralized network operation (e.g., where lack of a global view ofnetwork or need of additional communications for state exchange mayresult in poorer performance, if not designed carefully). For example,various example embodiments for supporting multi-tier deterministicnetworking, by supporting balance between centralized and decentralizednetwork operation, may be configured to handle any additional complexitythat may be introduced by physical and/or virtual topology changesintroduced due to mobility in different time scales and for variousreasons. For example, various example embodiments for supportingmulti-tier deterministic networking may be configured to supportdeterministic networking while overcoming various challenges which maybe faced in large networks (e.g., handling global or partial networkstate changes, gathering context information, prediction of metrics, orthe like). For example, various example embodiments for supportingmulti-tier deterministic networking may be configured to supportdeterministic networking while overcoming various potential issuesrelated to overhead in computation and communication due to schedulingand/or allocation mechanisms that might otherwise overuse various typesof resources. For example, various example embodiments for supportingmulti-tier deterministic networking may be configured to enable productsempowered by time-sensitive networking protocol stacks (e.g., IEEE TSNand IETF DetNet protocol stacks), which typically focus on small localareas for deterministic network communications, to bring deterministicnetworking to larger areas. For example, various example embodiments forsupporting multi-tier deterministic networking may be configured tosupport one or more of representation of a hierarchical clusterednetwork topology compatible with latency-based zoning in deterministicnetworking, hierarchical allocation/deallocation of deterministicresources in time-sensitive networks, identification and coordination ofnetwork entities for end-to-end deterministic flow communications,construction of end-to-end deterministic paths for deterministic flowsin a federated manner, deterministic networking in larger geographicalareas, or the like, as well as various combinations thereof. Forexample, various example embodiments for supporting multi-tierdeterministic networking may be configured to provide theabove-described advantages or potential advantages and/or overcome theabove-described challenges as well as various other challenges, whilestill supporting bounded deterministic performance constraints forvarious types of deterministic measures (e.g., latency, jitter,reliability, or the like). Various example embodiments for supportingmulti-tier deterministic networking may provide various other advantagesor potential advantages.

It will be appreciated that various example embodiments for supportingmulti-tier deterministic networking may be configured to support variousother functions for supporting multi-tier deterministic networking.

Various example embodiments for supporting multi-tier deterministicnetworking may be configured to supporting flow reliability inmulti-tier deterministic networking. Various example embodiments forsupporting flow reliability in multi-tier deterministic networking maybe configured to support flow reliability in multi-tier deterministicnetworking based on use of frame replication and elimination fordeterministic flows. Various example embodiments for supporting flowreliability in multi-tier deterministic networking may be configured tosupport flow reliability in multi-tier deterministic networking based oncontrol over frame replication and elimination for deterministic flows.

FIG. 6 depicts an example embodiment of a communication systemconfigured to support deterministic networking reliability based on flowreplication and elimination.

In FIG. 6 , the communication system 600 supports reliability fordeterministic networking. The reliability for deterministic networkingmay be based on use of redundant flows to protect deterministic flows.The reliability for a deterministic flow based on use of a redundantflow to protect at least a portion of the deterministic flow may bebased on use of deterministic flow replication/elimination capabilitiesalong the path of the deterministic flow. The reliability for adeterministic flow based on use of deterministic flowreplication/elimination capabilities along the path of the deterministicflow may be based on use of a replication function configured toreplicate the deterministic flow to provide the redundant flow for thedeterministic flow and an elimination function configured to eliminatethe redundant flow for the deterministic flow. It will be appreciatedthat one or more such pairs of replication and elimination functions maybe used along a deterministic flow to provide reliability for one ormore portions of the deterministic flow. It will be appreciated that, byreplicating flows, sending flows on separate paths, and then usingsequence numbers to eliminate replicas, the effective probability ofpacket loss is reduced or minimized and reliability of the deterministicflows is increased or maximized.

In FIG. 6 , the communication system 600 includes a similar arrangementof nodes as in the communication system 100 of FIG. 1 , including theclustering of the nodes as well as the hierarchical arrangement of thenodes. The communication system 600 includes a deterministic flow 620along the path C↔D↔F↔K↔M↔L. The communication system 600 includes tworedundant flows 621-1 and 621-2 (collectively, redundant flows 621)configured to protect portions of the deterministic flow 620. Namely,the redundant flow 621-1 follows the path D E↔H↔K that protects theportion of the deterministic flow 620 between nodes D and K (based on areplication function performed at node D and an elimination functionperformed at node K) and the redundant flow 621-2 follows the path M↔N↔Lthat protects the portion of the deterministic flow 620 between nodes Mand L (based on a replication function performed at node M and anelimination function which is located downstream and which, for purposesof clarity, is omitted from FIG. 6 ).

It will be appreciated that various example embodiments for supportingflow reliability in multi-tier deterministic networking may beconfigured to support various other functions for supporting flowreliability in multi-tier deterministic networking.

Various example embodiments for supporting multi-tier deterministicnetworking may be configured to support adaptive deterministic routingin multi-tier deterministic networks.

Various example embodiments for supporting adaptive deterministicrouting in multi-tier deterministic networks may be configured tosupport an agent-based adaptive flow routing mechanism. Various exampleembodiments for supporting adaptive deterministic routing in multi-tierdeterministic networks may be configured to support an agent-basedadaptive flow routing mechanism where deterministic communications maybe based on IEEE TSN, IETF DetNet, or the like. For example, variousexample embodiments of the agent-based adaptive flow routing mechanismmay be used for IETF DetNet network architectures or, more generally, inmulti-tier networks with a relatively large number of clusters. Forexample, various example embodiments of the agent-based adaptive flowrouting mechanism may be configured to use signaling and controlmechanisms of the IEEE TSN protocol stack to seamlessly allocate anddeallocate resources for deterministic flows. In this manner, the IETFDetNet and IEEE TSN protocol stacks may allow the routing protocol toachieve the goal of deterministic networking for various deterministicperformance measured, in various environments in which deterministicnetworking may be applied, or the like, as well as various combinationsthereof. For example, various example embodiments of the agent-basedadaptive flow routing mechanism may be configured to support agent-basedhierarchical flow allocation and routing capabilities for deterministicclustered networks. For example, various example embodiments of theagent-based adaptive flow routing mechanism may be configured to enablenodes to dynamically find end-to-end paths that can meet deterministicperformance targets such as bounded latency and jitter. For example,various example embodiments of the agent-based adaptive flow routingmechanism may be configured to leverage a clustered multi-tier IPnetwork, empowered by IEEE TSN and/or IETF DetNet protocol stacks, whileexploiting deep reinforcement (machine) learning techniques which candynamically approximate the state/search space of path finding. Forexample, various example embodiments of the agent-based adaptive flowrouting mechanism may be configured to enable nodes to find and proposepaths between two endpoints, and to dynamically adapts the searchdepending on network conditions and deterministic targets, irrespectiveof whether the target network is a clustered multi-tiered network or anon-hierarchical network. For example, various example embodiments ofthe agent-based adaptive flow routing mechanism may be configured tosupport a balance between the shortest path and the least congested pathwhile also taking into account hierarchical clustered aspects of thenetwork in a distributed manner as well as deterministic traffic whichmay be transported within such a network. For example, various exampleembodiments of the agent-based adaptive flow routing mechanism may beconfigured to support various other functions for supporting adaptivedeterministic routing.

Various example embodiments for supporting adaptive deterministicrouting in multi-tier deterministic networks may be further understoodby considering the networks of FIG. 1 , FIG. 2 , FIG. 3 , and/or FIG. 6. It will be appreciated that the multi-tier deterministic network inwhich adaptive deterministic routing is applied may be formed in variousways, e.g., statically (e.g., using approaches defined by the networkoperator), dynamically using algorithmic approaches (e.g., withpredefined intents, constraints, and performance conditions),dynamically as presented herein with respect to FIG. 2 and FIG. 3 , orthe like, as well as various combinations thereof.

FIG. 7 depicts an example embodiment of a method for supportingprovisioning of a deterministic flow in a multi-tier hierarchicalnetwork. For purposes of clarity, the method 700 is primarily describedwithin the context of an example based on FIG. 3 in which node A wishesto communicate to node N using a deterministic flow or based on FIG. 6in which node C wishes to communicate to node L using a deterministicflow.

At block 710, the group leaders and controllers with deep reinforcementlearning-based path recommendation agents perform initial training fromtheir historical records, and keep updating their states. The groupleader nodes and controllers, each of them having a learning agent, canbe trained and queried for a potential action that translates into afeasible link/sub-path which may be used later to compile a final path.The training procedure remains ongoing in an asynchronous fashion. Apath recommendation agent and environment may have the properties andbehavior as presented in FIG. 8 .

At block 720, a source node x sends a flow path computation request toits group leader g_(x) for deterministic transmission. This request isforwarded to the nearest “differentiating” controller. Thedifferentiating controller is a controller that has global knowledge ofall group leaders under its administration, potentially somewhere up inthe hierarchy, not always necessarily the top controller.

At block 730, the differentiating controller queries feasibleinter-cluster and intra-cluster paths within sub-controllers (orneighbor group leaders depending on the topology), resulting inrecursive queries initiated by controllers. Each sub-controller orneighbor group leader (acting as an environment) receiving a respectivequery interacts with its agent to find and schedule resources for alink/sub-path under its administration.

At block 740, when a controller or group leader that receives a query toresolve a link/sub-path, the corresponding “path agent” state is updatedand is triggered to “pick” an action.

At block 750, all initiated queries are resolved with a link/sub-pathschedule, and query results are forwarded to the initiating controllers.

At block 760, the differentiating controller compiles all queries andbuilds the final path details for the deterministic flow. The result isforwarded to respective group leaders of the source and destinationnodes.

At block 770, the source node x, relay nodes, and destination nodesreceive configuration and resource allocation/unallocation results fromtheir respective group leader(s). In case of failure of allocating theresources in any node, the differentiating controller is expected to beinformed by the related node(s), in which case it relays thisinformation to all relevant entities of the path.

At block 780, the source node x and the network nodes perform thedeterministic communication, since all resources along the path areallocated.

FIG. 8 depicts an example embodiment of a node including a pathrecommendation agent configured to determine a path for a deterministicflow. It will be appreciated that the path recommendation agent in thenode 800 of FIG. 8 may be suitable for use in performing various blocksof the method 700 of FIG. 7 (e.g., block 710).

In FIG. 8 , the agent 810 is an adaptive flow agent configured tosupport learning and link/sub-path recommendations.

In FIG. 8 , the environment 820 represents an abstraction of a groupleader node or controller (e.g., internal state and mechanics of a groupleader node or controller), which interacts with its agent when alink/sub-path recommendation is needed.

In FIG. 8 , a query message 831 might arrive from controllers or othergroup leaders to resolve a flow routing request between two nodes, anddepending on the configuration and administrative restrictions, theenvironment 820 then (1) updates its internal state (discussed in detailfurther below) that is shared with the agent 810 via an update statesignal s, (2) triggers a pick signal p to compute feasible link/sub-pathrecommendations by the agent 810, (3) choses one of the link/sub-pathcandidates (namely proposed actions/recommendations) according to itsheuristic preferences, and (4) informs the requesting group leader orcontroller about link/sub-path choice via a query response message 839.

In FIG. 8 , after the usage of the related link/sub-path is completedfor a given flow, the environment 820 then expects to receive a delayedfeedback message 832 from involved controllers such that it cancalculate a reward function. The result of reward function, namelyreward r, is shared with the agent 810 via internal signaling. Inaddition to this, the environment 820 might also receive other types offeedback messages (e.g., inter/intra-cluster link load status and otherkey performance indicators) with the ultimate aim of having a betterstate representation of the network for routing decisions.

In FIG. 8 , given an observed state matrix as input and a set ofinternal parameters θ quantifying weights between internal elements, theagent 810 is essentially a deep neural network that can propose actionsa, whenever requested via the pick signal p. The output of the deepneural network is action scores π(s, a) and is a vector that representsa list of normalized preferences for potential actions from which theenvironment 820 can chose. Each of these actions, depending on thedesign of input and neural network nodes, can represent a candidatelink/sub-path while considering the combinatorial nature of feasiblepossibilities.

In FIG. 8 , the environment 820 keeps a state representation fordeterministic flow scheduling that is shared with the agent 810. Thestate representation for deterministic flow scheduling may be a two (ormore) dimensional state matrix which may be padded with zeroes asneeded. An example of such a state matrix providing a staterepresentation for deterministic flow scheduling is presented in FIG. 9.

In FIG. 9 , the state matrix 900 maintained by a node for supportingdeterministic flow scheduling includes three blocks that represent thescheduled sub-paths, candidate deterministic flow sub-paths that arewaiting to be scheduled, and support metrics, respectively.

In FIG. 9 , the scheduled sub-paths are represented in the first blockof the matrix. This scheduled sub-paths block in the matrix representsthe information about scheduled deterministic sub-paths that isdistributed across multiple interfaces of the environment (which mightinclude multiple interfaces with various bandwidth requirements, latencyrequirements, or other type of requirements). The rows represent theamount of resource usage over time slots, and the columns represent theamount of resources in a given location. For example, a scheduled flowin with horizontal cross-hatching is consuming two units of bandwidthboth at interface K and interface N at time slot 1, and again will beconsuming two units of bandwidth at the next time slot (time slot 2). Itwill be appreciated that, although primarily presented with respect touse of bandwidth requirements in the state representation, various othertypes of requirements may be specified within the state representation(e.g., blocks for delay requirements, blocks for other resourcerequirements, or the like, as well as various combinations thereof forsupporting deterministic and time-sensitive transmissions.

In FIG. 9 , candidate deterministic flow links/sub-paths that arrive tothe scheduling system (waiting to be scheduled) are represented in themiddle block of the matrix. For example, Flow sub path 1 requires twounits of bandwidth resources at interface L at time slot 1, and alsorequires two units of bandwidth resources at interface N at time slot 1.It is noted that, since the number of candidate link/sub-path schedulingrequests that arrive to system can be large, the matrix may berestricted to represent only first predefined number of arrivals as anapproximation and the rest may be quantified in a sub-path backlog blockmaintained as part of the last block of the matrix. It is noted that,although only two arrived feasible sub-path choices for the same flow(represented with the vertical hatching) are depicted for purposes ofclarity, there might be multiple feasible solutions of multiple flowswhich may be represented within the matrix.

In FIG. 9 , certain support metrics are represented in the last block ofthe matrix. These metrics may include various metrics which mayfacilitate a more efficient scheduling of deterministic flows. One suchmetric, as indicated above, may be the sub-path backlog block. Othermetrics, as illustrated in FIG. H, may include local and global keyperformance indicator (KPI) metrics, which could be related to linkstates, a reward function, or the like. It will be appreciated that thelast block of the matrix may include various other metrics configured tofacilitate a more efficient scheduling of deterministic flows.

In FIG. 8 , the agent 810, whenever requested by the environment 820 viaa pick signal p, considers its input and weights, and proposes a vectorof action scores/preferences. Here, each action score a at the outputrepresents a numerical score/value for given feasible links/sub-pathsthat are waiting in the environment 820. Given these preferences, theenvironment 820 effectively decides to act on the highest scored action,meaning it puts the selected solution into its scheduled queue andupdates its state. The scheduled interfaces for such a route, asdescribed herein, is disseminated to the related controllers via thequery response 839.

It will be appreciated that as the system keeps operating in this mannerthen, ultimately, every controller and group leader (each of them havingtheir own agent) contributes to a hierarchical recursive system of pathfinding in the clustered network.

FIG. 10 depicts an example embodiment of a method for supportingprovisioning of a deterministic flow in a multi-tier hierarchicalnetwork. It will be appreciated that although primarily presented asbeing performed serially, at least a portion of the blocks of method1000 may be performed contemporaneously or in a different order than aspresented in FIG. 10 . At block 1001, the method 1000 begins. At block1010, receive, by an element of a communication network, a request toresolve a routing request for a deterministic flow. At block 1020,determine, by the element based on an adaptive sub-path determinationagent supported by the element and based on state information maintainedby the adaptive sub-path determination agent, a set of feasiblesub-paths for the deterministic flow. At block 1030, select, by theelement from the set of feasible sub-paths for the deterministic flowbased on scoring of the set of feasible sub-paths for the deterministicflow by the adaptive sub-path determination agent, a selected sub-pathfor the deterministic flow. At block 1040, send, by the element, aresponse indicative of the selected sub-path for the deterministic flow.At block 1099, the method 1000 ends.

Various example embodiments for supporting adaptive deterministicrouting in multi-tier deterministic networks may provide variousadvantages or potential advantages. For example, various exampleembodiments for supporting adaptive deterministic routing in multi-tierdeterministic networks may be configured to dynamically find end-to-endpaths that can meet deterministic performance targets such as boundedperformance measures (e.g., latency, jitter, or the like). For example,various example embodiments for supporting adaptive deterministicrouting in multi-tier deterministic networks may be configured to findand propose paths between endpoints while also adapting the searchdepending on various factors (e.g., network conditions, deterministictargets, or the like, as well as various combinations thereof). Forexample, various example embodiments for supporting adaptivedeterministic routing in multi-tier deterministic networks may beconfigured to leverage a clustered multi-tier IP network empowered byIEEE TSN and IETF DetNet protocol stacks and exploit deep reinforcement(machine) learning techniques which can dynamically approximatestate/search space of path finding. For example, various exampleembodiments for supporting adaptive deterministic routing in multi-tierdeterministic networks, based on the capability of hierarchicalmulti-tiered clustered networks to strike a balance between fullycentralized and distributed approaches, may be configured to provide amore scalable solution for large-scale deterministic networks. Forexample, various example embodiments for supporting adaptivedeterministic routing in multi-tier deterministic networks may beconfigured to provide an agent-based learning system and path findingmechanism that may capture several features of machine-learningempowered route finding mechanisms in networks. For example, variousexample embodiments for supporting adaptive deterministic routing inmulti-tier deterministic networks may be configured to bringdeterministic resource allocation to a larger geographical region. Forexample, various example embodiments for supporting adaptivedeterministic routing in multi-tier deterministic networks may beconfigured to support representation of hierarchical clustered networktopology compatible with latency-based zoning for frame replication andelimination in deterministic networking, hierarchical allocation anddeallocation of deterministic resources in deterministic networks,resolution of deterministic end-to-end paths in a federated manner,learning of partial network state for optimal routing in deterministiccommunications, discovery and updating of link and flow states fordeterministic routing, enabling deterministic networking in largergeographical areas, or the like, as well as various combinationsthereof. Various example embodiments for supporting adaptivedeterministic routing in multi-tier deterministic networks may providevarious other advantages or potential advantages.

It will be appreciated that various example embodiments for supportingmulti-tier deterministic networking may be configured to support variousother functions for supporting adaptive deterministic routing inmulti-tier deterministic networks.

It will be appreciated that, although primarily presented within thecontext of supporting adaptive deterministic routing in particular typesof clustered networks (namely, multi-tier deterministic networks),various example embodiments for supporting adaptive deterministicrouting as presented herein may be applied in various other types ofclustered networks.

Various example embodiments for supporting multi-tier deterministicnetworking may be configured to support score-based deterministicrouting in multi-tier deterministic networks.

Various example embodiments for supporting score-based deterministicrouting in multi-tier deterministic networks may be configured tosupport a score-based distributed flow routing mechanism. Variousexample embodiments for supporting score-based deterministic routing inmulti-tier deterministic networks may be configured to support ascore-based flow routing mechanism where deterministic communicationsmay be based on IEEE TSN, IETF DetNet, or the like. For example, variousexample embodiments of the score-based flow routing mechanism may beused for IETF DetNet network architectures (e.g., in order to enablefully deterministic networking) or, more generally, in multi-tiernetworks with a relatively large number of clusters. For example,various example embodiments of the score-based flow routing mechanismmay be configured to use signaling and control mechanisms of the IEEETSN protocol stack to seamlessly allocate and deallocate resources fordeterministic flows. For example, various example embodiments of thescore-based flow routing mechanism may be configured to use the IEEE TSNprotocol stack to deliver packets with bounded performance guarantees.In this manner, the IETF DetNet and IEEE TSN protocol stacks may allowthe routing protocol to achieve the goal of deterministic networking forvarious deterministic performance measured, in various environments inwhich deterministic networking may be applied, or the like, as well asvarious combinations thereof. For example, various example embodimentsof the score-based flow routing mechanism may be configured to supportscore-based hierarchical flow allocation and routing capabilities fordeterministic clustered networks. For example, various exampleembodiments of the score-based flow routing mechanism may be configuredto enable nodes to find end-to-end deterministic flow paths that cansatisfy deterministic performance targets such as bounded latency andjitter. For example, various example embodiments of the score-based flowrouting mechanism may be configured to leverage a clustered multi-tierIP network, empowered by IEEE TSN and/or IETF DetNet protocol stacks,while exploiting a score-based bin-packing-like heuristic that candynamically find feasible paths between pairs of endpoints. For example,various example embodiments of the score-based flow routing mechanismmay be configured to utilize techniques which can dynamicallyapproximate the state/search space of path finding. For example, variousexample embodiments of the score-based flow routing mechanism may beconfigured to enable nodes to find and propose paths between twoendpoints, and to dynamically adapts the search depending on networkconditions and deterministic targets, irrespective of whether the targetnetwork is a clustered multi-tiered network or a non-hierarchicalnetwork. For example, various example embodiments of the score-basedflow routing mechanism may be configured to support a balance betweencentralized and decentralized flow allocation while also taking intoaccount hierarchical clustered aspects of the network as well asdeterministic traffic which may be transported within such a network.For example, various example embodiments of the score-based flow routingmechanism may be configured to support various other functions forsupporting adaptive deterministic routing.

Various example embodiments for supporting score-based deterministicrouting in multi-tier deterministic networks may be further understoodby considering the networks of FIG. 1 , FIG. 2 , FIG. 3 , and/or FIG. 6. It will be appreciated that the multi-tier deterministic network inwhich score-based deterministic routing is applied may be formed invarious ways, e.g., statically (e.g., using approaches defined by thenetwork operator), dynamically using algorithmic approaches (e.g., withpredefined intents, constraints, and performance conditions),dynamically as presented herein with respect to FIGS. 2-3 , or the like,as well as various combinations thereof.

FIG. 11 depicts an example embodiment of a method for supportingprovisioning of a deterministic flow in a multi-tier hierarchicalnetwork. For purposes of clarity, the method 1100 is primarily describedwithin the context of an example based on FIG. 3 in which node A wishesto communicate to node N using a deterministic flow or based on FIG. 6in which node C wishes to communicate to node L using a deterministicflow.

At block 1110, the group leaders and controllers with score-based pathrecommendation agents operate in an asynchronous manner. The groupleader nodes and controllers, each of them having an agent that can bequeried for a potential action that translates into a feasiblelink/sub-path, which may be used later to compile a final path. Ascore-based path recommendation agent and environment may have theproperties and behavior as presented in FIG. 12 .

At block 1120, a source node x sends a flow path computation request toits group leader g_(x) for deterministic transmission. This request isforwarded to the nearest “differentiating” controller. Thedifferentiating controller is a controller that has global knowledge ofall group leaders under its administration, potentially somewhere up inthe hierarchy, not always necessarily the top controller.

At block 1130, the differentiating controller queries feasibleinter-cluster and intra-cluster paths within sub-controllers (orneighbor group leaders depending on the topology), resulting inrecursive queries initiated by controllers. Each sub-controller orneighbor group leader (acting as an environment) receiving a respectivequery interacts with its agent to find and schedule resources for alink/sub-path under its administration.

At block 1140, when a controller or group leader that receives a queryto resolve a link/sub-path, the corresponding “path agent” state isupdated and is triggered to “pick” an action.

At block 1150, all initiated queries are resolved with a link/sub-pathschedule, and query results are forwarded to the initiating controllers.

At block 1160, the differentiating controller compiles all queries andbuilds the final path details for the deterministic flow. The result isforwarded to respective group leaders of the source and destinationnodes.

At block 1170, the source node x, relay nodes, and destination nodesreceive configuration and resource allocation/unallocation results fromtheir respective group leader(s). In case of failure of allocating theresources in any node, the differentiating controller is expected to beinformed by the related node(s), in which case it relays thisinformation to all relevant entities of the path.

At block 1180, the source node x and the network nodes perform thedeterministic communication, since all resources along the path areallocated.

FIG. 12 depicts an example embodiment of a node including a score-basedpath recommendation agent configured to determine a path for adeterministic flow. It will be appreciated that the score-based pathrecommendation agent in the node 1200 of FIG. 12 may be suitable for usein performing various blocks of the method 1100 of FIG. 11 (e.g., block1110).

In FIG. 12 , the agent 1210 is a score-based flow agent configured tosupport learning and link/sub-path recommendations.

In FIG. 12 , the environment 1220 represents an abstraction of a groupleader node or controller (e.g., internal state and mechanics of a groupleader node or controller), which interacts with its agent when alink/sub-path recommendation is needed.

In FIG. 12 , a query message 1231 might arrive from controllers or othergroup leaders to resolve a flow routing request between two nodes, anddepending on the configuration and internal state, the environment 1220then (1) refreshes its internal state (discussed in detail furtherbelow) that is shared with the agent 1210 via an update state signal s,(2) sends a pick signal p to the agent 1210 to find a potentiallink/sub-path for the flow routing request, (3) choses one of thelink/sub-path candidates (namely proposed actions/recommendations) givenby the agent 1210, and (4) informs the requesting group leader orcontroller about link/sub-path choice via a query response message 1239.

In FIG. 12 , after the usage of the related link/sub-path is freed froma given flow, the environment 1220 then receives a delayed feedbackmessage 1232 from related controllers such that it can calculate areward function. This reward function can be measuring differencebetween expected and actual flow completion time or any other relevantperformance metric. The result of reward function, namely reward r, iscommunicated to the agent 1210 via internal signaling between theenvironment 1220 and its agent 1210. In addition to this, theenvironment 1220 might also receive other types of feedback messages(e.g., inter/intra-cluster link load status and other key performanceindicators) with the ultimate aim of having a better staterepresentation of the network for resource optimization.

In FIG. 12 , given an observed state matrix as input, the agent 1210 isessentially a score calculator of feasible links/sub-paths which can beproposed by the agent 1210 when requested via the pick signal p. Theoutput of the score calculator is called action scores π(s, a) and is avector that represents a list of potential actions with score values,effectively representing recommendations for links/sub-paths.

In FIG. 12 , the environment 1220 keeps a state representation fordeterministic flow scheduling that is shared with the agent 1210. Thestate representation for deterministic flow scheduling may be a two (ormore) dimensional state matrix which may be padded with zeroes asneeded. The state representation for deterministic flow scheduling maybe a two (or more) dimensional state matrix which may be padded withzeroes as needed. An example of such a state matrix providing a staterepresentation for deterministic flow scheduling is presented in FIG. 13.

In FIG. 13 , the state matrix 1300 maintained by a node for supportingdeterministic flow scheduling includes three blocks that represent thescheduled sub-paths, candidate deterministic flow sub-paths that arewaiting to be scheduled, and support metrics, respectively. It is notedthat the state matrix 1300 of FIG. 13 is similar to the state matrix 900of FIG. 9 in terms of organization of the state information, but that adifferent example is presented.

In FIG. 13 , the scheduled sub-paths are represented in the first blockof the matrix. This scheduled sub-paths block in the matrix representsthe information about scheduled deterministic sub-paths that isdistributed across multiple interfaces of the environment (which mightinclude multiple interfaces with various bandwidth requirements, latencyrequirements, or other type of requirements). The rows represent theamount of resource usage over time slots, and the columns represent theamount of resources in a given location. For example, a scheduled flowin with horizontal hatching is consuming two units of bandwidth both atinterface K and interface N at time slot 1, and again will be consumingtwo units of bandwidth at the next time slot (time slot 2). It will beappreciated that, although primarily presented with respect to use ofbandwidth requirements in the state representation, various other typesof requirements may be specified within the state representation (e.g.,blocks for delay requirements, blocks for other resource requirements,or the like, as well as various combinations thereof for supportingdeterministic and time-sensitive transmissions.

In FIG. 13 , candidate deterministic flow links/sub-path that arrive tothe scheduling system (waiting to be scheduled) are represented in themiddle block of the matrix. For example, Flow sub path 1 requires twounits of bandwidth resources at interface L at time slot 1, and alsorequires two units of bandwidth resources at interface N at time slot 1.It is noted that, since the number of candidate link/sub-path schedulingrequests that arrive to system can be large, the matrix may berestricted to represent only first predefined number of arrivals as anapproximation and the rest may be quantified in a sub-path backlog blockmaintained as part of the last block of the matrix. It is noted that,although only two arrived feasible sub-path choices for the same flow(represented with the vertical hatching) are depicted for purposes ofclarity, there might be multiple feasible solutions of multiple flowswhich may be represented within the matrix.

In FIG. 13 , certain support metrics are represented in the last blockof the matrix. These metrics may include various metrics which mayfacilitate a more efficient scheduling of deterministic flows. One suchmetric, as indicated above, may be the sub-path backlog block. Othermetrics, as illustrated in FIG. 13 , may include local and global keyperformance indicator (KPI) metrics, which could be related to linkstates, a reward function, or the like. It will be appreciated that thelast block of the matrix may include various other metrics configured tofacilitate a more efficient scheduling of deterministic flows.

In FIG. 12 , the agent 1210, whenever requested by the environment 1220via a pick signal p, considers its input, and proposes a vector ofaction scores/preferences. Here, each action score a at the outputrepresents a numerical score/value for given feasible links/sub-pathsthat are waiting in the environment 1220. Each numerical score/value isa result of a score function that is a linear function composed of oneor more factors. Examples of these scoring functions may include ashortest link/sub-path first heuristic that scores actions in increasingorder of their duration, a packer or tetric-like heuristic that scoresactions in increasing order of alignment between arrived links/sub-pathsand resource availability, a multi-dimensional in packer heuristic, anyother score calculation considering internal state and waitinglinks/sub-paths, or the like, as well as various combinations thereof.

In FIG. 12 , given these preferences, the environment 1220 effectivelydecides to act on the highest scored action, meaning it puts theselected solution into its scheduled queue and updates its state. Thescheduled interfaces for such a route, as described herein, isdisseminated to the related controllers via the query response 1239.

It will be appreciated that as the system keeps operating in this mannerthen, ultimately, every controller and group leader (each of them havingtheir own agent) contributes to a hierarchical recursive system of pathfinding in the clustered network.

FIG. 14 depicts an example embodiment of a method for supportingprovisioning of a deterministic flow in a multi-tier hierarchicalnetwork. It will be appreciated that although primarily presented asbeing performed serially, at least a portion of the blocks of method1400 may be performed contemporaneously or in a different order than aspresented in FIG. 14 . At block 1401, the method 1400 begins. At block1410, receive, by an element of a communication network, a request toresolve a routing request for a deterministic flow. At block 1420,determine, by the element based on a score-based sub-path determinationagent supported by the element and based on state information maintainedby the score-based sub-path determination agent, a set of feasiblesub-paths for the deterministic flow. At block 1430, select, by theelement from the set of feasible sub-paths for the deterministic flowbased on scoring of the set of feasible sub-paths for the deterministicflow by the score-based sub-path determination agent, a selectedsub-path for the deterministic flow. At block 1440, send, by theelement, a response indicative of the selected sub-path for thedeterministic flow. At block 1499, the method 1400 ends.

Various example embodiments for supporting score-based deterministicrouting in multi-tier deterministic networks may provide variousadvantages or potential advantages. For example, various exampleembodiments for supporting score-based deterministic routing inmulti-tier deterministic networks may be configured to dynamically findend-to-end paths that can meet deterministic performance targets such asbounded latency and jitter. For example, various example embodiments forsupporting score-based deterministic routing in multi-tier deterministicnetworks may be configured to find and propose paths between endpointswhile also adapting the search depending on various factors (e.g.,network conditions, deterministic targets, or the like, as well asvarious combinations thereof). For example, various example embodimentsfor supporting score-based deterministic routing in multi-tierdeterministic networks may be configured to leverage a clusteredmulti-tier IP network empowered by IEEE TSN and IETF DetNet protocolstacks and exploit a score-based bin-packing-like heuristic that canhierarchically find feasible paths between points. For example, variousexample embodiments for supporting score-based deterministic routing inmulti-tier deterministic networks, based on the capability ofhierarchical multi-tiered clustered networks to strike a balance betweenfully centralized and distributed approaches, may be configured toprovide a more scalable solution for large-scale deterministic networks.For example, various example embodiments for supporting score-baseddeterministic routing in multi-tier deterministic networks may beconfigured to provide a score-based agent and path finding mechanismthat may capture several heuristics for route finding mechanisms innetworks. For example, various example embodiments for supportingscore-based deterministic routing in multi-tier deterministic networksmay be configured to bring deterministic resource allocation to a largergeographical region. For example, various example embodiments forsupporting score-based deterministic routing in multi-tier deterministicnetworks may be configured to support representation of a hierarchicalclustered network topology compatible with latency-based zoning forframe replication and elimination in deterministic networking,hierarchical allocation and deallocation of deterministic resources indeterministic networks, resolution of deterministic end-to-end paths ina federated manner, heuristically finding routes for optimal routing indeterministic communications, discovery and updating of link and flowstates for deterministic routing, enabling deterministic networking inlarger geographical areas, or the like, as well as various combinationsthereof. Various example embodiments for supporting score-baseddeterministic routing in multi-tier deterministic networks may providevarious other advantages or potential advantages.

It will be appreciated that various example embodiments for supportingmulti-tier deterministic networking may be configured to support variousother functions for supporting score-based deterministic routing inmulti-tier deterministic networks.

FIG. 15 depicts an example embodiment of a method for supportingprovisioning of a deterministic flow in a multi-tier hierarchicalnetwork. It will be appreciated that although primarily presented asbeing performed serially, at least a portion of the blocks of method1500 may be performed contemporaneously or in a different order than aspresented in FIG. 15 . At block 1501, the method 1500 begins. At block1510, receive, by an element of a communication network, a request toresolve a routing request for a deterministic flow. At block 1520,determine, by the element based on a sub-path determination agentsupported by the element and based on state information maintained bythe sub-path determination agent, a set of feasible sub-paths for thedeterministic flow. At block 1530, select, by the element from the setof feasible sub-paths for the deterministic flow based on scoring of theset of feasible sub-paths for the deterministic flow by the sub-pathdetermination agent, a selected sub-path for the deterministic flow. Atblock 1540, send, by the element, a response indicative of the selectedsub-path for the deterministic flow. At block 1599, the method 1500ends.

FIG. 16 depicts an example embodiment of a method for supportingprovisioning of a deterministic flow in a multi-tier hierarchicalnetwork. It will be appreciated that although primarily presented asbeing performed serially, at least a portion of the blocks of method1600 may be performed contemporaneously or in a different order than aspresented in FIG. 16 . At block 1601, the method 1600 begins. At block1610, receive, by an element of a communication network configured tosupport a set of interfaces of a set of nodes of the communicationnetwork, a request to resolve a routing request for a deterministicflow. At block 1620, determine, by the element based on stateinformation for the set of interfaces, a sub-path for the deterministicflow, wherein the state information includes scheduled sub-pathinformation for a set of scheduled deterministic flow sub-pathsallocated on the set of interfaces and candidate sub-path informationfor a set of candidate deterministic flow sub-paths requested on the setof interfaces. At block 1630, send, by the element, a responseindicative of the selected sub-path for the deterministic flow. At block1699, the method 1600 ends.

FIG. 17 depicts an example embodiment of a system configured to supportmulti-tier deterministic networking. The system 1700 includes anadministrative domain 1701 including a set of routers 1710 and anadministrative authority 1720. The administrative domain 1701 may bedefined at any suitable granularity, which may be based on variousfactors (e.g., a regional telco network, a datacenter, a universitycampus network, or the like). The administrative domain 1701 may bearranged hierarchically in two or more tiers, with the administrativeauthority 1720 (and possibly one or more routers 1610) at the top tierand the routers 1710 arranged in one or more lower tiers. The routers1710 include SDN capabilities represented as SDN controllers 1711associated with the routers 1710, respectively. The routers 1710 areconfigured to support multi-tier deterministic networking. The routers1710 may interact with each other in the administrative domain,depending on roles, in order to support multi-tier deterministicnetworking as presented herein. The administrative authority 1720 isconfigured to control various aspects of the operation of the routers1710, such as supporting capabilities for configuring, monitoring, andmanaging the routers 1710. It is noted that, while omitted for purposesof clarity, an API may be available to non-router entities of theadministrative domain 1701 which are willing to use end-to-enddeterministic transmission through the network (e.g., a personalcomputer or smartphone connected to the network, an edge computer orbase station delivering information to one or more other networkelements, or the like), thereby enabling end users and applications todynamically leverage deterministic capabilities of networkprogrammability as needed or desired. It will be appreciated that, whileprimarily presented with respect to example embodiments in which eachrouter is equipped with an SDN controller, in at least some exampleembodiments only a portion of the SDN controllers (e.g., SDN controllersof routers 1710 located in one or more upper tiers of the hierarchy) maybe used to support example embodiments for supporting multi-tierdeterministic networking, in at least some example embodiments only aportion of the routers 1710 may include SDN controllers, or the like, aswell as various combinations thereof. It will be appreciated that,although presented with respect to a particular arrangement of therouters 1710, the routers 1710 may be arranged in various othertopologies (e.g., tree-like, leaf-spine, or using any other suitabletopologies) or even an arbitrary connectivity structure with a tieredmechanism.

Various example embodiments for supporting multi-tier deterministicnetworking may provide various advantages or potential advantages. Forexample, various example embodiments for supporting multi-tierdeterministic networking may be configured to support provisioning ofdeterministic flows in multi-tier deterministic networking, adaptivedeterministic routing in multi-tier deterministic networks, score-baseddeterministic routing in multi-tier deterministic networks, or the like,as well as various combinations thereof. Various example embodiments forsupporting multi-tier deterministic networking may provide various otheradvantages or potential advantages.

FIG. 18 depicts an example embodiment of a computer suitable for use inperforming various functions presented herein.

The computer 1800 includes a processor 1802 (e.g., a central processingunit (CPU), a processor, a processor having a set of processor cores, aprocessor core of a processor, or the like) and a memory 1804 (e.g., arandom access memory, a read only memory, or the like). The processor1802 and the memory 1804 may be communicatively connected. In at leastsome example embodiments, the computer 1800 may include at least oneprocessor and at least one memory including a set of instructions,wherein the set of instructions is configured to, when executed by theat least one processor, cause the computer to perform various functionspresented herein.

The computer 1800 also may include a cooperating element 1805. Thecooperating element 1805 may be a hardware device. The cooperatingelement 1805 may be a process that can be loaded into the memory 1804and executed by the processor 1802 to implement various functionspresented herein (in which case, for example, the cooperating element1805 (including associated data structures) can be stored on anon-transitory computer-readable storage medium, such as a storagedevice or other suitable type of storage element (e.g., a magneticdrive, an optical drive, or the like)).

The computer 1800 also may include one or more input/output devices1806. The input/output devices 1806 may include one or more of a userinput device (e.g., a keyboard, a keypad, a mouse, a microphone, acamera, or the like), a user output device (e.g., a display, a speaker,or the like), one or more network communication devices or elements(e.g., an input port, an output port, a receiver, a transmitter, atransceiver, or the like), one or more storage devices (e.g., a tapedrive, a floppy drive, a hard disk drive, a compact disk drive, or thelike), or the like, as well as various combinations thereof.

It will be appreciated that computer 1800 may represent a generalarchitecture and functionality suitable for implementing functionalelements described herein, portions of functional elements describedherein, or the like, as well as various combinations thereof. Forexample, computer 1800 may provide a general architecture andfunctionality that is suitable for implementing one or more elementspresented herein, such as a network devices (e.g., routers, switches, orthe like), network controllers, or the like, as well as variouscombinations thereof.

It will be appreciated that at least some of the functions presentedherein may be implemented in software (e.g., via implementation ofsoftware on one or more processors, for executing on a general purposecomputer (e.g., via execution by one or more processors) so as toprovide a special purpose computer, and the like) and/or may beimplemented in hardware (e.g., using a general purpose computer, one ormore application specific integrated circuits, and/or any other hardwareequivalents).

It will be appreciated that at least some of the functions presentedherein may be implemented within hardware, for example, as circuitrythat cooperates with the processor to perform various functions.Portions of the functions/elements described herein may be implementedas a computer program product wherein computer instructions, whenprocessed by a computer, adapt the operation of the computer such thatthe methods and/or techniques described herein are invoked or otherwiseprovided. Instructions for invoking the various methods may be stored infixed or removable media (e.g., non-transitory computer-readable media),transmitted via a data stream in a broadcast or other signal bearingmedium, and/or stored within a memory within a computing deviceoperating according to the instructions.

It will be appreciated that the term “or” as used herein refers to anon-exclusive “or” unless otherwise indicated (e.g., use of “or else” or“or in the alternative”).

It will be appreciated that, although various embodiments whichincorporate the teachings presented herein have been shown and describedin detail herein, those skilled in the art can readily devise many othervaried embodiments that still incorporate these teachings.

What is claimed is:
 1. An apparatus, comprising: at least one processor;and at least one memory storing instructions that, when executed by theat least one processor, cause the apparatus at least to: receive, by anode configured to operate within a multi-tier communication networkincluding at least a first tier and a second tier, a request to supporta deterministic flow, wherein the node is configured to operate as acluster leader for a cluster of nodes of the first tier and tocommunicate with a controller of the second tier; send, by the nodetoward the controller of the second tier based on a determination by thenode that the deterministic flow is unable to be resolved within thecluster of nodes of the first tier, the request to support thedeterministic flow; and receive, by the node from the controller of thesecond tier, a response indicative as to whether the deterministic flowhas been resolved within the multi-tier communication network.
 2. Theapparatus of claim 1, wherein the second tier includes a set of nodes,wherein the set of nodes includes the cluster of nodes of the first tierand includes a second cluster of nodes of the first tier that is managedby a second cluster leader.
 3. The apparatus of claim 1, wherein thedetermination by the node that the deterministic flow is unable to beresolved within the cluster of nodes of the first tier is based on anidentification vector of a source node of the deterministic flow and anidentification vector of a destination node of the deterministic flow.4. The apparatus of claim 3, wherein the identification vector of thesource node of the deterministic flow includes an identifier of thesource node within the cluster of nodes of the first tier, an identifierof the cluster of nodes of the first tier, and an identifier of a secondcluster of nodes of the second tier with which the source node isassociated.
 5. The apparatus of claim 3, wherein the identificationvector of the destination node of the deterministic flow includes anidentifier of the destination node within a second cluster of nodes ofthe first tier with which the destination node is associated, anidentifier of the second cluster of nodes of the first tier with whichthe destination node is associated, and an identifier of a secondcluster of nodes of the second tier with which the destination node isassociated.
 6. The apparatus of claim 1, wherein the determination bythe node that the deterministic flow is unable to be resolved within thecluster of nodes of the first tier is based on identification of amismatch between a first cluster identifier of a first cluster of nodesof the first tier with which the source node is associated and a secondcluster identifier of a second cluster of nodes of the first tier withwhich the destination node is associated.
 7. The apparatus of claim 1,wherein the instructions, when executed by the at least one processor,cause the apparatus at least to: send, by the node toward a second nodeof the deterministic flow that is located within the cluster of nodes ofthe first tier, configuration information for configuring the secondnode to support the deterministic flow.
 8. The apparatus of claim 1,wherein the instructions, when executed by the at least one processor,cause the apparatus at least to: allocate, at the node based on theresponse, resources for supporting the deterministic flow.
 9. Theapparatus of claim 8, wherein the resources for supporting thedeterministic flow include at least one of bandwidth resources or timeslot resources.
 10. The apparatus of claim 8, wherein the resources forsupporting the deterministic flow are allocated based on triggering of adeterministic protocol stack at the node.
 11. A method, comprising:receiving, by a node configured to operate within a multi-tiercommunication network including at least a first tier and a second tier,a request to support a deterministic flow, wherein the node isconfigured to operate as a cluster leader for a cluster of nodes of thefirst tier and to communicate with a controller of the second tier;sending, by the node toward the controller of the second tier based on adetermination by the node that the deterministic flow is unable to beresolved within the cluster of nodes of the first tier, the request tosupport the deterministic flow; and receiving, by the node from thecontroller of the second tier, a response indicative as to whether thedeterministic flow has been resolved within the multi-tier communicationnetwork.
 12. An apparatus, comprising: at least one processor; and atleast one memory storing instructions that, when executed by the atleast one processor, cause the apparatus at least to: receive, for amulti-tier communication network including at least a first tier and asecond tier, a request to support a deterministic flow, wherein therequest is received by a controller configured to control a cluster ofnodes of the second tier, wherein the request is received from a nodeoperating as a cluster leader of a cluster of nodes of the first tier,wherein the cluster of nodes of the first tier forms part of the clusterof nodes of the second tier; obtain, by the controller based on at leastone of a query to a second controller configured to control a secondcluster of nodes of the second tier or a query to a second nodeoperating as a cluster leader of a second cluster of nodes of the firsttier, information indicative of deterministic resources available withinthe multi-tier communication network to support the deterministic flow;and send, by the controller toward the node operating as the clusterleader of the cluster of nodes of the first tier, a response indicativeas to whether the deterministic flow has been resolved within themulti-tier communication network.
 13. The apparatus of claim 12, whereinthe information indicative of deterministic resources available withinthe multi-tier communication network to support the deterministic flowis obtained based on the query to the second controller configured tocontrol the second cluster of nodes of the second tier and the query tothe second node operating as the cluster leader of the second cluster ofnodes of the first tier.
 14. The apparatus of claim 13, wherein, toobtain the information indicative of deterministic resources availablewithin the multi-tier communication network to support the deterministicflow, the instructions, when executed by the at least one processor,cause the apparatus at least to: receive, by the controller, a firstresponse to the query to the second controller configured to control thesecond cluster of nodes of the second tier and a second response to thequery to the second node operating as the cluster leader of the secondcluster of nodes of the first tier; and determine, based on the firstresponse and the second response, the information indicative ofdeterministic resources available within the multi-tier communicationnetwork to support the deterministic flow.
 15. The apparatus of claim12, wherein the query to the second controller configured to control thesecond cluster of nodes of the second tier includes a query for feasibleinter-cluster paths between the first cluster of nodes of the secondtier and the second cluster of nodes of the second tier.
 16. Theapparatus of claim 12, wherein the query to the second node operating asthe cluster leader of the second cluster of nodes of the first tierincludes at least one of a query for feasible intra-cluster paths of thesecond cluster of nodes of the first tier or a query for feasibleinter-cluster paths between the first cluster of nodes of the first tierand the second cluster of nodes of the first tier.
 17. The apparatus ofclaim 12, wherein the second cluster of nodes of the first tier formspart of the cluster of nodes of the second tier.
 18. The apparatus ofclaim 12, wherein the second cluster of nodes of the first tier formspart of a second cluster of nodes of the second tier.
 19. The apparatusof claim 12, wherein the deterministic resources include at least one ofbandwidth resources or time slot resources.
 20. A method, comprising:receiving, for a multi-tier communication network including at least afirst tier and a second tier, a request to support a deterministic flow,wherein the request is received by a controller configured to control acluster of nodes of the second tier, wherein the request is receivedfrom a node operating as a cluster leader of a cluster of nodes of thefirst tier, wherein the cluster of nodes of the first tier forms part ofthe cluster of nodes of the second tier; obtaining, by the controllerbased on at least one of a query to a second controller configured tocontrol a second cluster of nodes of the second tier or a query to asecond node operating as a cluster leader of a second cluster of nodesof the first tier, information indicative of deterministic resourcesavailable within the multi-tier communication network to support thedeterministic flow; and sending, by the controller toward the nodeoperating as the cluster leader of the cluster of nodes of the firsttier, a response indicative as to whether the deterministic flow hasbeen resolved within the multi-tier communication network.